Well, the Azusa events later in the year have 30 slots free, so I'm guessing 30.

KD = "known distance" which is kind of an odd way to word it. Normal Appleseeds are shot at 25m using scaled targets. KD shoots are shot further out. I don't know how they do it at Azusa but typically they start at the shorter distances and then as things progress they peel off the more advanced students to the longer distances if they have a rifle that can reach out that far.